Semiconductor-on-insulator constructions

ABSTRACT

The invention encompasses a method of forming a semiconductor-on-insulator construction. A substrate is provided. The substrate includes a semiconductor-containing layer over an ins ulative mass. The insulative mass comprises silicon dioxide. A band of material is formed within the insulative mass. The material comprises one or more of nitrogen argon, fluorine, bromine, chlorine, iodine and germanium.

TECHNICAL FIELD

[0001] The invention pertains to semiconductor-on-insulatorconstructions (such as silicon-on-insulator constructions, orSiGe-on-insulator constructions), and to methods of formingsemiconductor-on-insulator constructions. In particular aspects, theinvention pertains to transistor devices associated withsemiconductor-on-insulator constructions, and methods of forming suchdevices.

BACKGROUND OF THE INVENTION

[0002] A prior art semiconductor-on-insulator construction is describedwith reference to FIG. 1. Specifically, FIG. 1 illustrates a fragment 10of a semiconductor-on-insulator construction. The construction includesa substrate 12 having an insulative material 14 formed thereover, andfurther comprises a semiconductor-containing material 16 formed overinsulative material 14.

[0003] Substrate 12 can comprise, for example, silicon and/or germanium.If the substrate comprises silicon, the silicon can be in the form of,for example, polycrystalline silicon and/or monocrystalline silicon. Toaid in interpretation of the claims that follow, the terms“semiconductive substrate” and “semiconductor substrate” are defined tomean any construction comprising semiconductive material, including, butnot limited to, bulk semiconductive materials such as a semiconductivewafer (either alone or in assemblies comprising other materialsthereon), and semiconductive material layers (either alone or inassemblies comprising other materials). The term “substrate” refers toany supporting structure, including, but not limited to, thesemiconductive substrates described above.

[0004] Insulative material 14 can comprise, consist essentially of, orconsist of silicon dioxide and/or nitrided oxides.

[0005] Semiconductor-containing material 16 can comprise, consistessentially of, or consist of monocrystalline silicon or othersemiconductor materials, such as, for example, SiGe heterostructures. Inparticular applications, semiconductor-containing material 16 willconsist essentially of, or consist of, monocrystalline silicon dopedwith either an n-type dopant or a p-type dopant, with an exemplaryp-type dopant being boron.

[0006] A transistor device 18 is shown associated withsemiconductor-containing material 16. Transistor device 18 includes atransistor gate 20 separated from semiconductor-containing material 16by a dielectric material 22, and includes source/drain regions 26 and28. Dielectric material 22 can comprise, for example, silicon dioxide,and can be referred to as a gate oxide. Gate 20 can comprise variousconductive materials, including, for example, metals, metal alloys,silicides, and/or conductively-doped silicon. In particularapplications, gate 20 will comprise a stack which includes, in ascendingorder from dielectric material 22, a layer of conductively-dopedsilicon, a layer of silicide, and a layer of metal.

[0007] Gate 20 defines a channel region 24 withinsemiconductor-containing material 16, and corresponding to a portion ofthe semiconductor-containing material 16 proximate the gate 20. In theshown construction, channel region 24 corresponds to the portion ofsemiconductor-containing material 16 immediately under gate 20, andseparated from gate 20 by dielectric material 22.

[0008] Sidewall spacers 30 are formed along sidewall edges of gate 20.Sidewall spacers can comprise, for example, silicon nitride and/orsilicon dioxide.

[0009] Source/drain regions 26 and 28 are formed withinsemiconductor-containing material 16, and separated from one another bychannel region 24. Source/drain regions 26 and 28 can comprise, forexample, n-type doped diffusion regions within semiconductor-containingmaterial 16 and/or p-type doped diffusion regions withinsemiconductor-containing material 16. In the shown construction, thesource/drain regions comprise a lightly-doped portion 32 beneath spacers30, and a heavily-doped portion 34 laterally outward of lightly-dopedportion 32 relative to channel region 24.

[0010] A continuing goal in semiconductor device fabrication is toreduce an amount of semiconductor real estate consumed by transistordevices. Several problems occur, however. For instance, problems canoccur as the length of channel region 24 between source/drain regions 26and 28 is decreased. Such problems are commonly referred to asshort-channel effects. A particular effect which is found to becomeproblematic is drain-induced barrier lowering (DIBL), which is due tocharge sharing between the source and drain of a transistor device. DIBLresults from lowering of a potential barrier at the source region due tohigh potential near the drain for short length devices.

[0011] It would be desirable to develop semiconductor constructionswhich alleviate, and preferably prevent, short-channel effects, as wellas to develop methods of forming such constructions.

SUMMARY OF THE INVENTION

[0012] In one aspect, the invention encompasses a method of forming asemiconductor-on-insulator construction. A substrate is provided. Thesubstrate includes a semiconductor-containing layer over an insulativemass. The insulative mass comprises silicon dioxide. A band of materialis formed within the insulative mass. The material comprises one or moreof nitrogen, argon, fluorine, bromine, chlorine, iodine and germanium.

[0013] In another aspect, the invention encompasses asemiconductor-on-insulator construction. The construction includes asubstrate having an insulative mass supported thereby. The insulativemass comprises silicon dioxide. A band of nitrogen is within theinsulative mass, and a semiconductor-containing layer is over theinsulative mass.

[0014] In yet another aspect, the invention encompasses transistordevices associated with semiconductor-on-insulator constructions, andmethods of forming such devices.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Preferred embodiments of the invention are described below withreference to the following accompanying drawings.

[0016]FIG. 1 is a diagrammatic, cross-sectional view of a fragment of aprior art semiconductor-on-insulator construction.

[0017]FIG. 2 is a diagrammatic, cross-sectional view of a fragment of aprior art-semiconductor-on-insulator construction.

[0018]FIG. 3 is a diagrammatic, cross-sectional view of the fragment ofFIG. 2 shown at a processing stage subsequent to that of FIG. 2 inaccordance with an aspect of the present invention.

[0019]FIG. 4 is a view of the FIG. 2 fragment shown at a processingstage subsequent to that of FIG. 3 in accordance with an aspect of thepresent invention.

[0020]FIG. 5 is a diagrammatic, cross-sectional view of a fragment of aprior art semiconductive material.

[0021]FIG. 6 is a view of the FIG. 5 fragment shown at a processingstage subsequent to that of FIG. 5 in accordance with an aspect of thepresent invention.

[0022]FIG. 7 is a view of the FIG. 5 fragment shown at a processingstage subsequent to that of FIG. 6 in accordance with an aspect of thepresent invention.

[0023]FIG. 8 is a diagrammatic and graphical view of a portion of theFIG. 3 structure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] A first aspect of the invention is described with reference toFIGS. 2-4. Referring initially to FIG. 2, a fragment 50 of a prior artsemiconductor-on-insulator construction is illustrated. Fragment 50comprises a substrate 52, an insulative mass 54 supported by thesubstrate, and a semiconductor-containing layer 56 (such as asilicon-containing layer or a SiGe-containing layer) over the insulativemass. Substrate 52 can comprise, for example, a semiconductive material,such as, for example, polycrystalline silicon and/or monocrystallinesilicon. Substrate 52 typically functions as a handle duringmanipulation of the semiconductor-on-insulator construction.

[0025] Insulative mass 54 can comprise, consist essentially of, orconsist of silicon dioxide. Mass 54 has a thickness 55, and suchthickness is typically from less than or equal to about 300 Å to about1,000 Å.

[0026] Semiconductor-containing material 56 can comprise, consistessentially of, or consist of SiGe or monocrystalline silicon, andtypically will comprise, consist essentially of, or consist ofmonocrystalline silicon doped with either p-type dopant or n-typedopant. An exemplary p-type dopant is boron, and exemplary n-typedopants are arsenic and phosphorous. Layer 56 comprises a thickness 57,and such thickness will typically be about 1,000 Angstroms.

[0027] In the shown construction, layer 56 physically contactsinsulative mass 54, and accordingly joins to insulative mass 54 at aninterface 58. A difficulty in forming semiconductor-on-insulatorconstructions can occur in attempting to form a uniform and tightinterface between mass 54 and layer 56. A good interface between mass 54and layer 56 would comprise a quick stoichiometric jump between thematerial of layer 54 (for example, silicon dioxide) and the material oflayer 56 (for example, silicon). However, interface 58 frequentlycomprises a region of diffusion between materials from mass 54 and layer56, and accordingly there is a diffused region of stoichiometric jumpbetween materials 54 and 56. Such region can comprise dangling bonds,which can produce acceptor/carrier trap sites. The trap sites cancontribute to short channel effects.

[0028] The construction 50 can be formed by numerous methods. Suchmethods can include starting with a monocrystalline substratecorresponding to layer 56, subsequently growing layers 54 and 52 overthe substrate, and then inverting the construction to form theconstruction 50 of FIG. 2. Methods can also include wafer bonding. Inwafer bonding methods, a first substrate can comprise layer 56 and aportion of insulative mass 54, a second substrate can comprise layer 52and another portion of insulative mass 54, and the two substrates can befused together at a high temperature to form the construction 50. In yetother methods, construction 50 can be formed by a so-called SIMOX (forseparation by implanted oxygen) method, in which a silicon substrate isinitially provided, and then oxygen is implanted into the substrate toform the silicon dioxide mass 54. The implanted oxygen simultaneouslydefines regions 52 and 56 within the substrate as the region 54 isformed.

[0029] Referring to FIG. 3, a material 60 is implanted through layer 56and into mass 54 to form a band 62 (or barrier) of the material withinmass 54. The band 62 will typically comprise a gradient of concentrationof material 60 (such as, for example, a gaussian distribution of theconcentration of material 60 as illustrated in FIG. 8), and a regionapproximately in the center of band 62 will comprise a peak (or highest)concentration of the barrier material. Such peak concentration region isillustrated diagrammatically with a dashed line 64. The peakconcentration of band 62 will preferably be within an upper half of mass54, and in particular applications can be within an upper third of mass54. Further, the peak concentration 64 within band 62 is preferably adistance 65 from the interface 58 between semiconductor-containing layer56 and mass 54 of at least about 100 Angstroms, and in particularapplications about 100 Angstroms to about 500 Angstroms from theinterface. In exemplary applications, an entirety of band 62 is withinthe upper half, or even upper third, of mass 54.

[0030] Barrier material 60 can comprise, consist essentially of, orconsist of, one or more of nitrogen, argon, fluorine, bromine, chlorine,iodine and germanium. If the material comprises one or more of nitrogen,argon, fluorine, bromine, chlorine, iodine and germanium, it is to beunderstood that the material can comprise compounds which include otherelements in addition to nitrogen, argon, fluorine, bromine, chlorine,iodine and germanium; as well as including compounds or compositionswhich do not comprise nitrogen, argon, fluorine, bromine, chlorine,iodine and germanium. However, the nitrogen, argon, fluorine, bromine,chlorine, iodine and/or germanium will be typically distributeduniformly throughout band 62. In applications in which the barriermaterial consists of one or more of nitrogen, argon, fluorine, bromine,chlorine, iodine and germanium, it is to be understood that the barriermaterial will only contain either atomic forms of nitrogen, argon,fluorine, bromine, chlorine, iodine and germanium; or compounds whichconsist only of nitrogen, argon, fluorine, bromine, chlorine, iodineand/or germanium. For instance, barrier material 62 can consist ofnitrogen, and include atomic nitrogen and/or diatomic nitrogen (N₂).

[0031] In particular applications, barrier material 60 will comprise,consist essentially of, or consist of, N₂. The N₂ can be implanted intoinsulative mass 54 at a dose of from about 5×10¹⁴ atoms/cm² to about2×10¹⁵ atoms/cm². The nitrogen can be implanted at about roomtemperature, and in particular applications can be implanted at atemperature of from about 0° C. to about 40° C. The peak nitrogenconcentration within mass 54 will preferably be at least about 1×10¹⁵atoms/cm³, and can be, in particular applications, at least about 1×10²⁰atoms/cm³.

[0032] Although the shown embodiment comprises implanting barriermaterial 60 after formation of semiconductor-containing layer 56 overmass 54, it is to be understood that barrier material 60 can also beimplanted prior to formation of the semiconductor-containing layer. Forinstance, an embodiment described below with reference to FIGS. 5-7illustrates implantation of material 60 into a semiconductor-containingsubstrate prior to formation of insulative mass 54 within the substrate.In yet another aspect, construction 50 can be formed by a wafer-bondingprocess. Band 62 can be provided within a substrate comprising mass 52and a portion of mass 54; and subsequently such substrate can be waferbonded to a second substrate comprising mass 56 and another portion ofmass 54. In such aspects, band 62 is formed within mass 54 prior toformation of layer 56 over the mass 54.

[0033] Referring to FIG. 4, a transistor device 18 is formed to beassociated with semiconductor-on-insulator construction 50. Device 18 inFIG. 4 is labeled with identical numbers as were utilized above indescribing the transistor device of FIG. 1, to indicate that transistordevice 18 of FIG. 4 can comprise the same materials and construction ofthe prior art device of FIG. 1. The barrier material within band 62 caninhibit, and in particular applications prevent, dopant diffusion andsegregation within semiconductor-containing layer 56 proximate interface58. Accordingly, the band of barrier material can alleviate, and inparticular applications prevent, dopant diffusion proximate channelregion 24 which would otherwise exacerbate short-channel effects.

[0034] An advantage of forming band 62 at least 100 Angstroms beneathinterface 58 is that such can avoid formation of additional trap stateswithin interface 58 resulting from the implant of the barrier material.However, band 62 should be close enough to interface 58 to have thedesired effect of alleviating (and in particular applicationspreventing) dopant diffusion within semiconductor-containing layer 56proximate interface 58, and accordingly band 62 is preferably within thetop half, and more preferably within the top third, of mass 54. Band 62can thus enable retention of high concentrations of both donor andacceptor levels in silicon near interface 58 (frequently referred to asa silicon/buried oxide (BOX) interface). Additionally, if the barriermaterial comprises N₂, transient-enhanced diffusion (TED) can occur toincrease dopant pile-up at interface 58, which can further help tocontrol short-channel effects.

[0035] The barrier material within band 62 is preferably subjected tohigh temperature processing (such as, for example, rapid thermalprocessing) after implantation of the barrier material within mass 54.Such thermal processing preferably occurs before formation ofsource/drain regions 26 and 28, to avoid diffusion of the dopantsutilized in the source/drain regions during the high temperatureprocessing. Exemplary high temperature processing of a barrier material(such as, for example, N₂) can comprise a high temperature (greater than1000° C.) furnace anneal in an inert ambient gas (such as, for example,N₂) for a time of from about 30 minutes to about 1 hour. Alternatively,the high temperature processing can comprise subjecting a barriermaterial to a rapid thermal anneal to greater than 1000° C. for a timeof from about 10 seconds to about 30 seconds.

[0036] The high temperature processing can anneal defects which occurwithin masses 54 and 56 during the implant of the barrier material.

[0037] An advantage of forming the nitrogen within the insulative mass54, rather than in other locations relative to transistor device 18, isthat such can limit diffusion of nitrogen into regions of the transistordevice where the nitrogen is unwanted. For instance, if nitrogen reachesan interface between gate oxide 22 and semiconductor-containing layer56, it can potentially increase interface charge density and trapstates, which can negatively impact device reliability. However, theformation of nitrogen within band 62 in mass 54 can effectivelysegregate the nitrogen from transistor device 18, and avoid negativeeffects of the nitrogen on the device.

[0038] Among the advantages that band 62 of the barrier material canoffer, relative to prior art constructions, (such as the construction ofFIG. 1) is better short channel effects control for threshold voltageadjustments in the channel region (24 of FIG. 4), as well as relative tohalo implant regions associated with source/drain regions 26 and 28.Additionally, an implant energy utilized for implanting the barriermaterial into the buried oxide 54 can be carefully controlled to implantthe nitrogen deep enough within mass 54 to avoid formation of trapstates, or other degradation, relative to interface 58 between mass 54and semiconductor-containing layer 56.

[0039] Further aspects of the invention are described with reference toFIGS. 5-7. Referring initially to FIG. 5, a fragment 100 of asemiconductor-containing mass 102 is illustrated.Semiconductor-containing mass 102 can comprise, for example, SiGe ormonocrystalline silicon, and in particular applications can be dopedwith n-type or p-type dopant, such as, for example, boron. Mass 102 can,for example, correspond to a fragment of a monocrystalline siliconwafer.

[0040] Referring to FIG. 6, barrier material 60 is implanted into mass102 to form band 62 of the barrier material.

[0041] Referring to FIG. 7, oxygen 104 is implanted into fragment 100 toform insulative mass 54 within the fragment, and simultaneously definethe region 52 beneath mass 54 and the semiconductor-containing layer 56over mass 54. The construction of FIG. 7 can correspond identically tothe construction of FIG. 3, and can be subjected to further processingto form a transistor device associated with the construction.

[0042] In compliance with the statute, the invention has been describedin language more or less specific as to structural and methodicalfeatures. It is to be understood, however, that the invention is notlimited to the specific features shown and described, since the meansherein disclosed comprise preferred forms of putting the invention intoeffect. The invention is, therefore, claimed in any of its forms ormodifications within the proper scope of the appended claimsappropriately interpreted in accordance with the doctrine ofequivalents.

1. A method of forming a semiconductor-on-insulator construction,comprising: providing a substrate comprising a semiconductor-containinglayer over an insulative mass, the insulative mass comprising silicondioxide; and forming a band of material within the insulative mass, thematerial comprising one or more of nitrogen, argon, fluorine, bromine,chlorine, iodine and germanium.
 2. The method of claim 1 wherein thesemiconductor-containing layer comprises one or both of Si and Ge. 3.The method of claim 1 wherein the material consists essentially of oneor more of nitrogen, argon, fluorine, bromine, chlorine, iodine andgermanium.
 4. The method of claim 1 wherein the material consists of oneor more of nitrogen, argon, fluorine, bromine, chlorine, iodine andgermanium.
 5. The method of claim 1 wherein the semiconductor-containinglayer is formed over the insulative mass, and wherein the band of thematerial is formed within the insulative mass prior to forming thesemiconductor-containing layer over the insulative mass.
 6. The methodof claim 1 wherein the semiconductor-containing layer is formed over theinsulative mass, and wherein the band of the material is formed withinthe insulative mass after forming the semiconductor-containing layerover the insulative mass.
 7. The method of claim 1 wherein theinsulative mass has a thickness, and wherein the material is formed tohave a peak concentration within an upper half of the thickness.
 8. Themethod of claim 1 wherein the insulative mass has a thickness, andwherein the material is formed to have a peak concentration within anupper third of the thickness.
 9. The method of claim 1 wherein thesemiconductor-containing layer physically contacts the insulative mass;wherein an interface is defined at a location where thesemiconductor-containing layer joins the insulative mass; and whereinthe material is formed to have a peak concentration at least 100Angstroms from the interface.
 10. The method of claim 1 wherein thesemiconductor-containing layer physically contacts the insulative mass;wherein an interface is defined at a location where thesemiconductor-containing layer joins the insulative mass; and whereinthe material is formed to have a peak concentration that is about 100 Åto about 500 Å from the interface.
 11. The method of claim 1 wherein thesemiconductor-containing layer comprises SiGe.
 12. The method of claim 1wherein the semiconductor-containing layer comprises monocrystallinesilicon.
 13. The method of claim 1 wherein the semiconductor-containinglayer consists essentially of monocrystalline silicon.
 14. The method ofclaim 1 wherein the material comprises germanium.
 15. The method ofclaim 1 wherein the material comprises argon.
 16. The method of claim 1wherein the material comprises one or more of fluorine, chlorine,bromine and iodine.
 17. The method of claim 1 wherein the materialcomprises nitrogen.
 18. A method of forming a semiconductor-on-insulatorconstruction, comprising: providing a substrate having an insulativemass supported thereby and having a semiconductor-containing layer overthe insulative mass, the insulative mass comprising silicon dioxide; andproviding nitrogen within the insulative mass.
 19. The method of claim18 wherein the semiconductor-containing layer comprises monocrystallinesilicon.
 20. The method of claim 18 wherein the semiconductor-containinglayer comprises SiGe.
 21. The method of claim 18 wherein the nitrogen isN₂.
 22. The method of claim 18 wherein the providing nitrogen comprisesimplanting N₂ into the insulative mass.
 23. The method of claim 18wherein the providing nitrogen comprises implanting N₂ into theinsulative mass at a dose of from about 5×10¹⁴ atoms/cm² to about 2×10¹⁵atoms/cm².
 24. The method of claim 18 wherein the providing nitrogencomprises implanting N₂ into the insulative mass at a dose of from about5×10¹⁴ atoms/cm² to about 2×10¹⁵ atoms/cm², the implanted N₂ being at atemperature of from about 0° C. to about 40° C.
 25. The method of claim18 wherein the nitrogen is formed to have a peak concentration of atleast about 1×10¹⁵ atoms/cm³ within the insulative mass.
 26. The methodof claim 18 wherein the nitrogen is formed to have a peak concentrationof at least about 1×10²⁰ atoms/cm³ within the insulative mass.
 27. Themethod of claim 18 wherein the providing nitrogen occurs prior to theproviding the semiconductor-containing layer.
 28. The method of claim 18wherein the providing nitrogen occurs after the providing thesemiconductor-containing layer.
 29. The method of claim 18 wherein thesemiconductor-containing layer is a monocrystalline silicon-containinglayer; wherein the insulative mass is formed by implanting oxygen intomonocrystalline silicon to form silicon dioxide within the substrate,and wherein the monocrystalline silicon-containing layer over theinsulative mass is defined simultaneously with the formation of theinsulative mass and comprises a segment of the monocrystalline siliconremaining over the insulative mass.
 30. The method of claim 18 whereinthe insulative mass has a thickness, and wherein the nitrogen is formedto have a peak concentration within an upper half of the thickness. 31.The method of claim 18 wherein the insulative mass has a thickness, andwherein the nitrogen is formed to have a peak concentration within anupper third of the thickness.
 32. The method of claim 18 wherein thesemiconductor-containing layer physically contacts the insulative mass;wherein an interface is defined at a location where thesemiconductor-containing layer joins the insulative mass; and whereinthe nitrogen is formed to have a peak concentration at least 100Angstroms from the interface.
 33. The method of claim 18 wherein thesemiconductor-containing layer physically contacts the insulative mass;wherein an interface is defined at a location where thesemiconductor-containing layer joins the insulative mass; and whereinthe nitrogen is formed to have a peak concentration that is about 100 Åto about 500 Å from the interface.
 34. A method of forming a transistordevice associated with semiconductor-on-insulator construction,comprising: providing a substrate comprising a semiconductor-containinglayer over an insulative mass, the insulative mass comprising silicondioxide; forming a band of material within the insulative mass, thematerial comprising one or more of nitrogen, argon, fluorine, bromine,chlorine, iodine and germanium; forming a transistor gate proximate thesemiconductor-containing layer, the transistor gate defining a channelregion within the semiconductor-containing layer; and forming a pair ofsource/drain regions within the semiconductor-containing layer andseparated from one another by the channel region.
 35. The method ofclaim 34 wherein the material consists essentially of one or more ofnitrogen, argon, fluorine, bromine, chlorine, iodine and germanium. 36.The method of claim 34 wherein the material consists of one or more ofnitrogen, argon, fluorine, bromine, chlorine, iodine and germanium. 37.The method of claim 34 wherein the semiconductor-containing layer isformed over the insulative mass, and wherein the band of the material isformed within the insulative mass prior to forming thesemiconductor-containing layer over the insulative mass.
 38. The methodof claim 34 wherein the semiconductor-containing layer is formed overthe insulative mass, and wherein the band of the material is formedwithin the insulative mass after forming the semiconductor-containinglayer over the insulative mass.
 39. The method of claim 34 wherein theinsulative mass has a thickness, and wherein the material is formed tohave a peak concentration within an upper half of the thickness.
 40. Themethod of claim 34 wherein the insulative mass has a thickness, andwherein the material is formed to have a peak concentration within anupper third of the thickness.
 41. The method of claim 34 wherein thesemiconductor-containing layer physically contacts the insulative mass;wherein an interface is defined at a location where thesemiconductor-containing layer joins the insulative mass; and whereinthe material is formed to have a peak concentration at least 100Angstroms from the interface.
 42. The method of claim 34 wherein thesemiconductor-containing layer physically contacts the insulative mass;wherein an interface is defined at a location where thesemiconductor-containing layer joins the insulative mass; and whereinthe material is formed to have a peak concentration that is about 100 Åto about 500 Å from the interface.
 43. The method of claim 34 whereinthe semiconductor-containing layer comprises SiGe.
 44. The method ofclaim 34 wherein the semiconductor-containing layer comprisesmonocrystalline silicon.
 45. The method of claim 34 wherein thesemiconductor-containing layer comprises n-type doped monocrystallinesilicon.
 46. The method of claim 34 wherein the semiconductor-containinglayer comprises p-type doped monocrystalline silicon.
 47. The method ofclaim 34 wherein the semiconductor-containing layer comprises borondoped monocrystalline silicon.
 48. The method of claim 34 wherein thesemiconductor-containing layer consists essentially of monocrystallinesilicon.
 49. The method of claim 34 wherein the material comprisesgermanium.
 50. The method of claim 34 wherein the material comprisesargon.
 51. The method of claim 34 wherein the material comprises one ormore of fluorine, chlorine, bromine and iodine.
 52. The method of claim34 wherein the material comprises N₂.
 53. A semiconductor-on-insulatorconstruction, comprising: a substrate comprising asemiconductor-containing layer over an insulative mass, the insulativemass comprising silicon dioxide; and a band of material within theinsulative mass, the material comprising one or more of nitrogen, argon,fluorine, bromine, chlorine, iodine and germanium.
 54. The constructionof claim 53 wherein the material consists essentially of one or more ofnitrogen argon, fluorine, bromine, chlorine, iodine, and germanium. 55.The construction of claim 53 wherein the material consists of one ormore of nitrogen, argon, fluorine, bromine, chlorine, iodine andgermanium.
 56. The construction of claim 53 wherein the insulative masshas a thickness, and wherein a peak concentration of the material iswithin an upper half of the thickness.
 57. The construction of claim 53wherein the insulative mass has a thickness, and wherein a peakconcentration of the material is within an upper third of the thickness.58. The construction of claim 53 wherein the semiconductor-containinglayer physically contacts the insulative mass; wherein an interface isdefined at a location where the semiconductor-containing layer joins theinsulative mass; and wherein a peak concentration of the material is atleast 100 Angstroms from the interface.
 59. The construction of claim 53wherein the semiconductor-containing layer physically contacts theinsulative mass; wherein an interface is defined at a location where thesemiconductor-containing layer joins the insulative mass; and wherein apeak concentration of the material is about 100 Å to about 500 Å fromthe interface.
 60. The construction of claim 53 wherein thesemiconductor-containing layer comprises SiGe.
 61. The construction ofclaim 53 wherein the semiconductor-containing layer comprisesmonocrystalline silicon.
 62. The construction of claim 53 wherein thesemiconductor-containing layer consists essentially of monocrystallinesilicon.
 63. The construction of claim 53 wherein the material comprisesgermanium.
 64. The construction of claim 53 wherein the materialcomprises argon.
 65. The construction of claim 53 wherein the materialcomprises one or more of fluorine, chlorine, bromine and iodine.
 66. Theconstruction of claim 53 wherein the material comprises N₂.
 67. Asilicon-on-insulator construction, comprising: a substrate having aninsulative mass supported thereby, the insulative mass comprisingsilicon dioxide; a band of nitrogen within the insulative mass; and asilicon-containing layer over the insulative mass.
 68. The constructionof claim 67 wherein the nitrogen is comprised by N₂.
 69. Theconstruction of claim 67 wherein a peak concentration of the nitrogenwithin the insulative mass is at least about 1×10¹⁵ atoms/cm³.
 70. Theconstruction of claim 67 wherein a peak concentration of the nitrogenwithin the insulative mass is at least about 1×10²⁰ atoms/cm³.
 71. Theconstruction of claim 67 wherein the insulative mass has a thickness,and wherein a peak concentration of the nitrogen is within an upper halfof the thickness.
 72. The construction of claim 67 wherein theinsulative mass has a thickness, and wherein a peak concentration of thenitrogen is within an upper third of the thickness.
 73. The constructionof claim 67 wherein the silicon-containing layer physically contacts theinsulative mass; wherein an interface is defined at a location where thesilicon-containing layer joins the insulative mass; and wherein a peakconcentration of the nitrogen is at least 100 Angstroms from theinterface.
 74. The construction of claim 67 wherein thesilicon-containing layer physically contacts the insulative mass;wherein an interface is defined at a location where thesilicon-containing layer joins the insulative mass; and wherein a peakconcentration of the nitrogen is about 100 Å to about 500 Å from theinterface.
 75. A semiconductor construction, comprising: a substratecomprising a silicon-containing layer over an insulative mass, theinsulative mass comprising silicon dioxide; a band of barrier within theinsulative mass, the material being selected from the group consistingof nitrogen, argon, fluorine, bromine, chlorine, iodine, germanium, andmixtures thereof; a transistor gate proximate the silicon-containinglayer, the transistor gate defining a channel region within thesilicon-containing layer; and a pair of source/drain regions within thesilicon-containing layer and separated from one another by the channelregion.
 76. The construction of claim 75 wherein the insulative mass hasa thickness, and wherein a peak concentration of the material is withinan upper half of the thickness.
 77. The construction of claim 75 whereinthe insulative mass has a thickness, and wherein a peak concentration ofthe material is within an upper third of the thickness.
 78. Theconstruction of claim 75 wherein the silicon-containing layer physicallycontacts the insulative mass; wherein an interface is defined at alocation where the silicon-containing layer joins the insulative mass;and wherein a peak concentration of the material is at least 100Angstroms from the interface.
 79. The construction of claim 75 whereinthe silicon-containing layer physically contacts the insulative mass;wherein an interface is defined at a location where thesilicon-containing layer joins the insulative mass; and wherein a peakconcentration of the material is about 100 Å to about 500 Å from theinterface.
 80. The construction of claim 75 wherein thesilicon-containing layer comprises monocrystalline silicon.
 81. Theconstruction of claim 75 wherein the silicon-containing layer comprisesn-type doped monocrystalline silicon.
 82. The construction of claim 75wherein the silicon-containing layer comprises p-type dopedmonocrystalline silicon.
 83. The construction of claim 75 wherein thesilicon-containing layer comprises boron doped monocrystalline silicon.84. The construction of claim 75 wherein the silicon-containing layerconsists essentially of monocrystalline silicon.
 85. The construction ofclaim 75 wherein the material comprises germanium.
 86. The constructionof claim 75 wherein the material comprises argon.
 87. The constructionof claim 75 wherein the material comprises one or more of fluorine,chlorine, bromine and iodine.
 88. The construction of claim 75 whereinthe material comprises N₂.